Abstract: A spraying apparatus is disclosed for spraying coating material onto an internal wall of a cylindrical structure having an opening. The apparatus includes a spraying assembly which has a first and a second end. A support is secured to the spraying assembly, the support being selectively movable relative to the opening of the structure for permitting movement of the second end of the spraying assembly axially relative to the structure. A first conduit has a first and a second extremity, the first extremity of the first conduit being connected to a source of a first component of the coating material. The second extremity of the first conduit is connected to the second end of the spraying assembly. A second conduit has a first and a second termination, the first termination of the second conduit being connected to a further source of a second component of the coating material. The second termination of the second conduit is connected to the second end of the spraying assembly.